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Nesting Season

Bird Nesting Season: What to do and not to do

Many birds nest during the spring and summer. Unfortunately, this is also the time of year that people tend to trim trees, prune shrubs, and clear brush. Severely cutting, trimming, and topping trees, bushes, reeds, and other greenery in the spring and summer can destroy nests and eliminate valuable nest sites. Any modification of vegetation during the nesting season may result in disturbance, abandonment, or death of nesting birds, eggs, or nestlings.

There are laws that protect birds, their nests, eggs, and young from being removed, destroyed or harassed. Violating any of these laws may result in fines and imprisonment.

Many species nest between March 1 and August 31. The California Department of Fish and Wildlife often requires surveys for raptor (bird of prey) nests from January 15 to September 15.

Several species court and nest outside this time frame, such as some herons and egrets, many raptors, and most hummingbirds. Depending on the species, nesting birds may be found at any time of year.

Consult an independent qualified biologist for safe trimming times upon discovering any nest.

Best Time to Trim Trees: September to February

It’s Illegal to Harm a Bird Nest!

If you witness tree trimmers or anyone disturbing or destroying an active nest (one with viable eggs or chicks), ask them to STOP!
Let them know it is against the law. (CA Fish & Game Code § 3503 (2018) Cite information about the California
Migratory Bird Protection Act and California State Code. If they do not cooperate, call the CALTIP number below; give exact information about location, cross streets, name of offending company, vehicle license plate number, etc.

  • Take photographs! Evidence is needed that birds are definitely nesting.

  • Find someone in authority such as a building manager, city staff, or park ranger to let them know what is happening.

  • Consider social media and the local press if the practice continues.

What to Know About Nesting Birds

According to Audubon California and local bird rehabilitators, most birds nest between February 1 and August 31 in Central
California. Great Horned Owls and Ravens begin nesting in January, while Orioles and Mockingbirds can nest through August, sometimes later. Certified bird rehabbers note that hummingbirds, hawks, owls and other nests are found any time of year.

  • Always check for active nests before trimming. Tree trimming during nesting season can result in destruction of nests, eggs and young birds.

  • Do not disturb large nests. Some birds reuse nests every year – beware of large stick nests of hawks, owls, crows, ravens, herons and egrets.

  • Most bird nests are well camouflaged. Songbirds conceal nests so they are virtually impossible to detect even by the best arborists.

  • Moving a nest is illegal and requires special permission from the U.S. Fish and Wildlife Service. If the nest with eggs or young is disturbed, the parent birds may abandon the nest.

Other Notes
  • California has two regulations protecting nesting birds, including the California Migratory Bird Protection Act of 2019 that supports the federal law Migratory Bird Treaty Act. Fines can be up to $500,000.

  • Most birds camouflage their nests, making it sometimes impossible for tree trimmers to see them.

  • If you witness tree pruning that is disturbing a nest or injuring nestlings, tell them to stop, and call 888-334-2258 (CALTIP) to report. Take photos and video.

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